Method of making lubricating apparatus



- Sept. 2, 1941. a F THOMAS ETAL, 2,254,503

METHOD OF MAKING LUBRICATING APPARATUS Original Filed Sept..30, 1935 3 Sheets-Sheet 1 Patented Sept. 2, 1941 APPARATUS George ilhomas,

Riverside, and Joseph 'Bystnicky, Chicago, 111., assignors -to Stewart- -Wa-nner Corporation, Chicago, 111., a corpora- 'tion-oflvirginia Original application September 30,1935, Serial No; 423746; Divide?! and this :appli'cation luly :1, I936, Serial No-.=88,270

l '10fClainis.

' Our invention relates generally to high pressure lubricating apparatus, and more particularly to an improved .rnethodiofrmakinglubricant receiving fittings and an improved method of securing the fitting to "a part to b8l1lbTlC3Itd. More broadly, the invention relates to an improved method of securing metalparts tnge'the'r by a threaded ping :and socket connection. EL-his application is :a division of sour fcoepeh'ding agpic'ation Serial :No. 42,746., September. 30, 1 3 o n ,An average automobile rhflcricated :by a high pressure lubricating :system hasin the'rord'er "of 30 bearings requiringhigh pressure ilubri'c'ation. It has been customary in the past to (secure the lubricant receiving fitting to the bearings "by drilling and tapping an 'oil hole in iii-rehearing and screwing the fitting thereinto. fllhe "additional cost of the tapping operation will be. a large fraction oflone cent, in'the order of -'onehalf cent per individual 'tappmg operation. Furthermore, the production of the bearingpartstis frequently delayed by breakage of tapswand 'by losses resulting from defective parts due to failureiofth'e :tanped hole to conform to the required standards of perfection of thread; Also, *chips and small particle'sof the metal are frequently left in the threaded oil :hole :as a result oi the tapping operation, and the removal or these chips is an operation addingto the cost of tapping oil holes in bearings. If the metallic chips resultant from the tapping operation are not carefully removed, damage to the bearing surfaces may result.

By the use of the fitting of our present invention the necessity of. tapping theoil holes in the bearing parts is entirely teliminated, it being necessary merely to drill the oil holes by usual drilling methods with the tolerances per- Initt'ed. We accom fl ish this resifl t' by providing a lubricant receiving'ii tting "with a hardened threaded shank portion which may 'be of sub stantially standard ,pipe thread 'pitch but may be of slightly greater taper and of 'difierent thread form, inserting the fitting. into a chilled oi-l hole, which is of slightly less diameter than the external diameter of the main ,portion' of the thread on the shank, and driving the fitting longitudinally into the drilled oil hole of the bearing, without rotating the fitting relative to the bearing. We also provide the fitting with a pilot portion by which the .fitting may be guided into the oil hole and which will serve as a means to catch and retain small chips which might (Cl. 29-157) I otherwiseefall into the heafingand score the bearing surfaces. f

Inthemeth'od of'securing the lubricant receiving fitting tofthe hearing which is described .5 herein, as the fitting is being driven into the oil holeof :the bearing, the hardened th're'adedshank portion of the fittingswages the metal of the bearing part' to form thereina female thread complemental to and meshing with that "on the ,10 fitting. 'Ihe'rconnection thus accomplished hetween'the'fitting and the bearing has been found to be very tight, being able to withstand lubricant pressures greater. than 10,000 Lpounds "per square inch It has also'ihe'en' found that by utilizing the method :of 'our invention the fitting may, if necessary, be readily removed from "the bearing part by ,iunscrewing it, since the thread formed in the oil hole. of the bearing is integral with the hearing and is approximately as strong 'as a tappedpthread;

The thread on thevfitt-ing is preferably 'of relatively low ipitch'and may, if 'desired, be of the same pitch as a -c'orresnonding standard :pipe

thread so thatg should it-become necessary to remove the fitting of our present invention, a fitting having a shank with a standard pipe thread thereon may be satisfactorily substituted for the fitting removed;

'30 The fitting may beatta'ched to the bearing :by means of being pressed thereinto by a punch press, or may be manually pounded into the bearing part. By either, method the time required to secure the fitting to the bearing part is considerably less than that required to screw a fitting in place.

From the above it will be apparent that one of the primary objects of our invention is to provide an improved form of lubricant receiving 40 fitting which may be economically manufactured,

which will eliminate the necessity of tapping the oil holes in the-bearings, and Which may be readily attached to the bearing part. v f :A further object is to provide an improved 4 method of making lubricant receiving fittings and to provide an improved method of securing the fittings to the parts-to :be lubricated.

Other objects will appear from the following description; reference being had to the accom- S O panying drawings, in which Figure 1 is -a view partly (inside elevation and partly in central vertical section, showing a fitting blank .as :it appears at the end of the forming operation;

Figure 2 is aside elevation of a fitting as it view of the complete assembled fitting;

Figure 5 is a view illustrating a tool which may be utilized to drive the fitting in place in the oil hole of the bearing, the bearing being shown in transverse cross section in this figure;

Figure 6 is a greatly enlarged longitudinal sec tional view of the shank portionof the fitting;

Figure 7 is a view showing one-halfof} the shank portion of the fitting in position to be driven into the oil hole of a bearing;

Figure 8 is a view similar to Figure 6, illustrating a stage in the operationofidriving' the fitting into the bearing;

Figure 9 is likewise a view similar to. Figure '7 showing the fitting in its final position after' it has been completely driven into the oil. hole'of the bearing; l o; 5

Figure 10 is a central longitudinalrisectional view of a modified form of fitting shown at tached to a bearing part; 5i; 2;.

Figure 11 is an elevational view of the lfitting shown in Figure 10 in position to be driven upon a projection forming part of a bearing; :l ,3"

Figure 12 is an enlarged vertical sectionalview of a second modified form of our invention shown in position ready to be driven into the oil hole of a bearing; and V g: V

Figures 13, 14 and 15. are greatly enlarged fragmentary sectional views of the shank of the fitting shown in Figure 12 and illustrating the successive stages as the fitting is being driven into the bearing. i 1 The fitting of our invention is preferably made of a steel which may be readily hardened: and which can be formed from wire stock on a cold heading machine. The blank thus produced by the cold heading operation is illustratedjin Figure 1 and comprises a head portion which'may be suitably conformed to make a mechanical and lubricant tight connection with the discharge coupler of a high pressure lubricant compressor. The head is formed integrally with a generally frustoconically shaped I part 22, a polygonal wrench engaging part 24, a tapered shank portion 26, a cylindrical portion 28, flange forming portion 30.

After the blank has been formed as illustrated in Figure 1, the fittinghas threads rolled upon be plated or otherwise suitably finished. After the fitting has been finished a ball check valve 44 is inserted in the valve chamber and a compression coil spring 46 is forced into this chamber, either by direct pressure or by rotating the spring so that it will feed itself into the chamber. When in position, as indicated in Figure 4, the lower coils of the spring 46 will rest upon the inner surface of the internally extend- The form of the thread rolled upon the shank of the fitting is of particular significance and is best illustrated in Figures 6 to 9, inclusive. The form angle of the thread is preferably approximately 90andthe root diameter of the thread preferably tapers at an angle of approximately 3.with respect to the axis of the fitting. The

.toporcrest of the thread is preferably fiat and the angle between the line drawn through the tops of'the 'convolutions of the thread and the axis of, thefitting showsatapering outer diameter forjthe tln'ead and is preferably'a greater angle the shank and pilot portions, resulting in the threaded blank as illustrated in Figure 2.

After the blank has been threaded it is drilled and counterbored as best illustrated in Figure 3 to form an inlet opening passageway 32, a by lindrical passageway 34 of slightly greater-idiameter than the passageway 32, acounterbore '36, a frusto conical valve seat 38,- and a' spring and check valve receiving counterbore 40. The

lower end of the fitting is bored to a diameter slightly greater than that of "the 'check 'valve' chamber 40, to forma depending annular flange 42. 1

After the fitting has been thus formed the flange lip 42 is bent inwardly to the position in which it is shown in Figure 4, and theshank portion 26 being preferably case hardened so that the threads thereon will be extremely hard. If desired,.the threadingoperation may be deferred until just previous to the hardening op eration.

and aspring than' 'the'corresponding angle ofa line drawn through the roots of the thread, being herein illustrated as an angle of 4. It will be noted that the pilot portion 28 of the shank has approi imately. two complete threads 48, 50, the fiat top' surfaces of which are cylindrical. The external diameter of the'threa'ds 48 and 50 is 6 preferably slightlyile'ss than the nominal diame-I ter of the drilled oil hole into which the fitting is to be inserted, as illustrated inFigure 7. These two threads thus'form a pilot'to guide the fit ting into the oil hole; 'I'helig'rooves above the threads designated 48 and serve as traps to catch and retain chipsor particles of metal that may possibly be'form'edas the fitting is forced intothebearingi xf M In Figure '7 axportion of the side wall of the bearing is indicated bythe reference character 52, and only a part of the shank portion of the fitting issliown inJthe position which it assumes when the fitting'is'placed in the oilhole of the bearing preparatory to driving it or pressing it into its-final position. It will be noted'that in this position the pilot threads 48 and 50 fit sufliciently'closely to the wall'of the oil hole of ;the bearinglthat the fitting is held in axial alignment withfthe'oilhole; a I

A driving-tool 54 (Figure 5) having a socket 56 in one end thereof and having a; flared surface 58 conformingto the shape of the generallyfrus toconically shaped part22 of the fitting,may be used to drive the fitting in place, the tool being struck :by hammer or sledge until its inward movement is arrestedrby the beveled shoulder so formed beneath 'thehexagonal portion 24 of the fitting. Y I

In Figure 8' the fitting'is shown driven partially into the bearing, to 'illustratehowthe tapered thread 62 swages a complementary thread-in the-bearing The thread 62 being case hardened willnot bedeformed. but will .cause the metal of the bearing to flow substantially in the manner as illustrated in ,Figure, 8., .The form angle of After the hardening operation the fittingni y 15 211 37 fo e In Figure '9 the fitting is illustratedas being driven-completely into ,the oil-hole of the bearing and a complete thread .65 complementary to :the thread I62 has been formed on the'bearing. The extent to which the fitting may :be :driven into the ;oil :hole of the bearing isJl'imited by the shoulder 50, a portion of which will be pressed into the metal of the bearing and :aid LinIJcausi-ng the metal :of the bearing to fiow beneath the topmost turn :of the thread 52, in order .to insure that the uppermost turn :of the thread :54 will be com- -plete and will form a seal with theadjacent surfaces of the thread '62. I-nasrnuch as pressures in the order of 10,000 pounds per square inch are frequently employed in the application of lubr-icant through fittings of the type herein illustrated, it is necessary notonly that the interlock between the fitting and bearing be suificiently strong that the fitting will not be loosened by accidental blows, and will not be-forced from the bearing by-the back pressure-of the lubricant, but also that the engaging threads fit each other sufiiciently tightly and snugly that the possibility of leakage between the threads is absolutely precluded.

From a consideration of the method by which the thread 64 is formed, as illustrated in Figures 7, '8 and 9, it will be observed that each turn of the thread 62 acts moreor less independently of the preceding and following turns to swage a turn of the thread 64 as the fitting driven into the oil hole of the bearing. Thus, at-least three, and under optimum conditions four, complete turns of a thread 64 are formed. Each turn of the thread '64 will in itself be capable of effectlug .a lubricant-tight seal,..and since there are at least three complete turns of the thread, the fitting will be sealed in the bearing even though a minor flaw in the .metallicstructure of the bearing might render one of the turns of the thread ineffective to :form a seal against the escape of lubricant.

Where the bearing part is of such form as to make it feasible, the fitting may be driven into the bearing part ina press. Due .to the fact that three or more complete turns ofv the thread 6'4 are formed in the bearing, the-fitting may be applied to bearings in which the surface is not plane, it being necessary that only one or two complete turns of the thread -64 be formed to prevent leakage of lubricant. I

Should the lowermost turn of the thread .52 loosen any chips of metal .from the bearing, .such chips will be caught in the grooves above the pilot threads 48 and 5.0 and prevented from falling into the bearing. Since the .pilot thread -48, 5.. is continuous with the thread 52, the fitting may readily be unscrewed from the bearing should the necessity therefor arise.

Furthermore, as previously stated, the thread on the fitting is preferably of standard pipe thread pitch so that if a damaged fitting is removed it may be replaced with a fitting having the standard pipe thread if another fitting of the type herein disclosed is not readily available.

The method of our invention may'be carried out withzfittings andiother (parts of :a "large number :of :slightly ;difierent forms, the construction illustrated :in Figures 112 to being representative-rot .one of:a number of possible variations. In these the :fitting is shown .as having a shank :66 ifiormed a tapered thread $8 which is 'of substantially the form and character :as the thread 5.2 in the .:construction previously described, except that the angle of the "taper is substantially greater. The'included angle of the taper may be in the order of 16 instead of 8.as the embodiment shown in Figures 1 to 9,

inclusive.

.In using a sitting of the construction shown in :Figures I2-to 15,- the oil hole of the bearing is I tapered at the same angle as the thread of the the oil hole ef-the-bearing with the female thread Since the fitting is driven into the oil hole of the bearing solely by longitudinal movement and is not rotated, the operation of securing the fitting into the bearing isvery simple and does not require the use of any complicated tools or ma chinery. Furthermore, since the thread formed in the bearing is swaged instead of being cut, the possibility of the formation of deleterious metallic chips is minimized.

in the "bearing fully formed and intermeshing with the thread -68 of the fitting. In this construction thenuni-ber'of turns of the thread which may be fer-med in the bearing part is considerably greater than the number of turns which may be 'formed with the fitting disclosed in Figs. 1 -to '9 inclusive. Each-turn of the thread is moved a distance only slightly greater than the pitch of the thread and thus the metal of which the thread is formed need not be displaced as far from its original position-as is required in the preferred construction of Figs. 1 to '9 inclusive. While the fitting of Figs. 12 to l5'inclusive thus has the advantage of forming a stronger mechanical and lubricantti ght bond between the fitting and.bearing, it has the disadvantage that a tapered hole in'the bearingis required and the cost of making "the tapered hole within the necessary dimensional limits may largely offset the saving effected by the elimination of the tapping operation,

In Figs. 10 and 11 we have shown a modified form of our invention inwhich the fitting body 7 3 has a threaded bore 1'2 :in which the threads l4 are of substantially the same form and taper as the threads in the embodiment of .our invention shown in Figs. 1 to '9 inclusive. The bore 12 is enlarged at its lower end so that a pilot thread 16 may be formed therein. In this construction the fitting body i0 is driven over a cylindrical projection 1810f a bearing part which is provided with a lubricant .conducting passageway 189, During the operation of the driving the fitting overthe projection 18 of the bearing part a helical thread 82 is swaged on the projection 18, said thread meshing with and tightly interengajging with the thread I 4 formed in the 'bore 12 of the body of the fitting. In the construction shown in Figs. 10 and 11 the spring 84 for the ball check valve .85 is seated upon lugs 88 dis placed from the body of the fitting-in the usual well known manner.

While we have shown and described the meth- 0d of our invention as applied to securing lubri cant receiving fittings to hearings, the fundam ntal pri iples of h invention a be e ployed in making various types of connections as a substitute for the usual screw thread connection. For' example, studs, bolts, nuts and machine screws may beprovided with a hard ened thread of the type herein disclosed and various. parts of tools, machinery, and equipment secured together by such fastening means. Our invention will have application wherever it is desired to secure two metal parts together, and particularly where the parts are to be detachably secured together and where the operation of tapping is an item of expense to be considered.

To those skilled in the art it will be readily apparent that the method of our invention may be carried out in a numberof slightly different ways and that various modifications in the dethe other part, wherebythe parts will be tightly secured together but may be separated by unscrewing one relative to the other.

5; The method of making a fluid tight joint between a' metallic plug member and a metallic socket member which comprises forming upon one of said members a rugged, hardened low pitch helical threadhaving a tapering outer diameter, forcing said plug member into said socket member by rectilinear non-rotative disv placement of one member relativerto the other,

tails of the form of the thread and changes in What we claim as new and desire to secure by Letters Patent of the United States is:

l. The method of securing metallic parts together which comprises. forming a number of turns of a low pitch thread having artapering outer diameter on one part, hardening said threads, forming a cylindrical bore in the other part, and driving the-parts together one into the cylindrical bore of the other by substantially rectilinear non-rotative relative movement causing each turn of the thread of the threaded part to swage complementary meshing turns of a continuous thread upon the other part, whereby the parts may be separated by unscrewing one relative to the other.

2. The method of securing metallic parts together which comprises forming a number of turns of a tapering outer diameter low pitch screw thread of substantially 90 V form upon one of the parts, forming a cylindrical bore in the other part, and driving the parts together one into the cylindrical bore of the other by substantially rectilinear non-rotative relative movement to cause each of several turns of the thread on the threaded part to swage complementary meshingfturns of a thread upon the other part, whereby the parts may be separated by unscrewing one relative to the other.

3. The method of securing metallic parts together which comprises forminghardened low pitch threads of generally 90 V form and tapering outer diameter on one part, hardening said threads, forming a cylindrical bore in the other part, and driving the parts together one into the cylindrical bore of the other by substantially translatory. relative movement without relative rotation to cause the threaded part alone to swage a complementary meshing thread upon the other part, whereby the parts will be secured together in fluid-tight interlocking engagement and maybe separated by unscrewing one relative to the other. 4

4. The method of securing metallic parts together which comprises forming a female low pitch hardened screw thread of substantially 90 \l-form and tapered outer diameter on one of the' parts, and driving said part over the other part by rectilinear non-rotative relative movement to cause the threaded part independently to swage a complementary meshing thread upon thereby causing each of several turns of the thread on the threaded memlberto swage complementary meshing turns of a thread upon the other of said members.

6. The method of securing a lubricant receiving metal fitting in a substantially cylindrical bore ,in a metal part to 'be lubricated, which comprises, forming a continuous thread on the shank of the fitting of taperedouter diameter, hardening the threaded part of the shank, and driving the shank of the fitting longitudinally into the hole of the part to be lubricated without relative rotation between the fitting and said part whereby the thread itself on the fitting will swage a complementary internal thread in the part to be lubricated.

7. The method of making -a fluid-tight joint between a tapered plug member and a socket member of metal, which comprises forming upon said plug member a hardened low pitch helical thread, the major portion of which is of greater diameter than the bore ofsaid socket member, forcing said plug member into said socket member solely by rectilinear displacement of one member relative to the other to cause displacement of metal solely from the walls of the bore of the socket member, thereby causing the thread on said plugmember to swage the metal displaced fromthe wall of the socket member into a complementary meshing thread.

8. The method of securing a lubrication fitting in a substantially cylindrical bore in a metal body, said lubrication fitting having a head and a shank formed with a screw thread, said thread being tapered from the portion nearest the head outwardly toward the end thereof, comprising, inserting the fittingshankin the bore with an inwardly facing surface thereof adapted to be exposed to the pressure of fluid within the bore, and forcing said shank into the bore by rectilinear non-rotative relative movement to cause turns of said thread to displace metal from the body into the groove between the displacing turns of the thread and a turn in advance thereof, to retain the shank in the bore against the action of lubricant pressure'on said surface and to seal the shank against lubricant'leakage therearound. r

9. The method of securing a lubrication fitting in a substantially cylindrical bore in a metal body, said lubrication fitting having a shank formed with a series of axially. displaced projections of successively increasing diameter in one direction with the smallest diameter less than that of the bore and the largest diameter greater 5 than'that of the bore,comprising, inserting the shank in the bore against the action of lubricant pressure on said surface and to seal the shank surface having a diameter intermediate the largest and smallest diameter of the ridged por-- tion of the irusto-iconical surface on the harder of said elements, whereby said ridge swages the metal subjacent said cylindrical surface in a progressive manner to form an interlocking ridge conformed to permit disengagement of the parts by application of a rotary couple thereto without further deformation of the metal of either of 10 said parts.

GEORGE F. THOMAS. JOSEPH BYSTRICKY.

CERTIFICATE OF CORRECTION.

Patent No. 2,25h,505. September 2, 19m.

GEORGE F. 'THOMAS, ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page l|.,' first column, line 61; claim 5, before "'translatory insert "rectilinear"; and said Letters Patent snouldbe read with this correction therein hat the e case in the Patent Office.

that the same may conform to the record of th Signed and sealed this 50th day of December, A. D. 191 1 Henry Van Arsdale (Seal) Acting Commie si'oner of Patents. 

